Electrically driven flywheel-fastener driver

Abstract

An electric fastener driver having a compact size and simple construction. A driver segment provided with a rack is movably disposed in a housing. A flywheel is driven by a motor. A drive shaft is concentric with and integral with the flywheel. A coil spring is fixed to the drive shaft. A driven rotor is coaxial with the drive shaft and has one end portion serving as a spring seat portion positioned within the coil spring. A pinion is disposed at the driven rotor and is meshedly engaged with the rack. An urging section is disposed within the driven rotor. A ball is movably disposed in a through-hole formed in the driven rotor for urging an end portion of the coil spring by the urging section. A solenoid controls a protruding amount of the ball from the surface of the driven rotor.

1. An electric fastener driver comprising:
 a housing having a fastener driving side; 
 a motor disposed in the housing; 
 a magazine attached to the housing for supplying a fastener to the fastener driving side; 
 a flywheel rotatably supported to the housing and driven by the motor; 
 a driven rotor rotatably supported to the housing; 
 a driver segment driven by the driven rotor and movable toward and away from the fastener driving side; 
 a coil spring that transmits a rotation force of the flywheel to the driven rotor; and 
 a clutch mechanism selectively coupling the flywheel to the driven rotor through the coil spring; 
 wherein the clutch mechanism is movable between a power transmission position at which the coil spring is coupled to the driven rotor and a power shut-off position at which the coil spring is separated from the driven rotor. 
 
   
   
     2. The electric fastener driver as claimed in  claim 1 , wherein the clutch mechanism comprises a solenoid that selectively urges the coil spring. 
   
   
     3. The electric fastener driver:
 as claimed in  claim 2 , wherein the driven rotor is of a cylindrical shape providing an interior hollow space, 
 and the solenoid has a solenoid plunger disposed within the interior hollow space. 
 
   
   
     4. The electric fastener driver as claimed in  claim 3 , wherein the solenoid plunger is associated with the clutch mechanism for driving the clutch mechanism. 
   
   
     5. The electric fastener driver as claimed in  claim 3 , further comprising a coil spring that transmits a rotation force of the flywheel to the driven rotor; and
 wherein the driven rotor is of a cylindrical shape and is formed with a through-hole extending in a radial direction thereof, and 
 wherein the clutch mechanism comprises a contact piece movable in the through-hole for urging the coil spring to couple the coil spring to the driven rotor. 
 
   
   
     6. The electric fastener driver as claimed in  claim 1 , wherein the coil spring has one end portion concentrically fixed to the flywheel, and another end portion disposed over the driven rotor having an outer diameter, the another end portion providing an inner diameter greater than the outer diameter of the driven rotor when the clutch mechanism is at the power shut-off position. 
   
   
     7. The electric fastener driver as claimed in  claim 6 , wherein the driven rotor is of a cylindrical shape providing an internal hollow space, and is formed with a through-hole extending in a radial direction thereof at a position in alignment with the another end portion, and the clutch mechanism further comprising a contact piece movable in the through-hole in the radial direction. 
   
   
     8. The electric fastener driver as claimed in  claim 7 , wherein the driven rotor has a spring seat section at a position in alignment with the through hole in the radial direction, the another end portion of the coil spring being nipped between the contact piece and the spring seat section when the clutch mechanism is at a power transmission position. 
   
   
     9. The electric fastener driver as claimed in  claim 7 , wherein the another end portion of the coil spring has a distal end portion extending in a direction to allow the contact piece to abut against the distal end portion when the clutch mechanism is at a power transmission position. 
   
   
     10. The electric fastener driver as claimed in  claim 7 , wherein the another end portion of the coil spring is connected to an annular flange segment, the through-hole having an open end in alignment with the annular flange segment for allowing the contact piece to be in direct contact with the annular flange segment. 
   
   
     11. The electric fastener driver as claimed in  claim 10 , wherein the driven rotor is formed with a plurality of through-holes extending in a radial direction thereof at a position in alignment with the another end portion and spaced away from each other at an equal interval in a circumferential direction of the driven rotor, and the clutch mechanism further comprising a plurality of contact pieces each movable in each through-hole in the radial direction. 
   
   
     12. The electric fastener driver as claimed in  claim 7 , wherein the clutch mechanism comprises a solenoid that selectively urges the coil spring, the solenoid comprising a solenoid plunger and an urging section driven by the solenoid plunger for urging the contact piece, at least a part of the solenoid plunger being disposed within the internal hollow space. 
   
   
     13. The electric fastener driver as claimed in  claim 12 , wherein the urging section is rotatable with respect to the solenoid plunger, and has a rotation axis coincident with a rotation axis of the flywheel. 
   
   
     14. The electric fastener driver as claimed in  claim 1 , wherein the driver segment has a fastener driving end and an opposite end, and
 the fastener driver further comprising a driver segment feed mechanism provided between the driven rotor and the driver segment for converting a rotary motion of the driven rotor into a linear motion of the driver segment in a direction from the opposite end to the fastener driving end, the feed mechanism comprising a rack provided at the driver segment and a pinion gear provided at the driven rotor and meshingly engaged with the rack. 
 
   
   
     15. The electric fastener driver as claimed in  claim 1 , wherein the driver segment has a fastener driving end and an opposite end, and
 the fastener driver further comprising a driver segment feed mechanism provided between the driven rotor and the driver segment for converting a rotary motion of the driven rotor into a linear motion of the driver segment in a direction from the opposite end to the fastener driving end, the feed mechanism comprising a wire having one end fixed to the opposite end, and another end fixed to the driven rotor. 
 
   
   
     16. An electric fastener driver comprising:
 a housing having a fastener driving side; 
 a motor disposed in the housing; 
 a magazine attached to the housing for supplying a fastener to the fastener driving side; 
 a flywheel rotatably supported to the housing and driven by the motor; 
 a drive shaft provided at the flywheel and having an outer peripheral surface; 
 a driven rotor rotatably supported to the housing and axially arrayed with and coaxial with the drive shaft, the driven rotor having an outer peripheral surface; 
 a driver segment driven by the driven rotor; 
 a coil spring that transmits a rotation force of the drive shaft to the driven rotor; and 
 a clutch mechanism selectively coupling the drive shaft to the driven rotor through the coil spring for selectively rotating the driven rotor, the drive shaft providing an outer diameter at a side of the driven rotor equal to an outer diameter of the driven rotor at a side of the drive shaft, and the outer peripheral surface of the drive shaft being continuous with the outer peripheral surface of the driven shaft.